The flow of sand on the southernmost tip of Lake Michigan is out of balance, creating serious erosion in some places and too much sand in others, experts say.

After decades of treating the problem at Indiana Dunes National Lakeshore in a more or less piecemeal fashion, the National Park Service is composing what it says is a comprehensive strategy to resolve the problem.

Months before a formal plan is released, however, the 20-year, nearly $41 million effort is tangled in controversy and faces a daunting path before work starts, if it ever does.

"I can pretty much guarantee that whatever solution they come up with will be something complicated, something costly and something that will require a great deal of cooperation between all the people involved," said Nicole Barker, executive director of Save the Dunes, which was established in 1952, 14 years before the area was declared a national park.

Today, close to 2 million people a year visit the 15,000-acre ecological gem wedged in an industrial landscape, according to the National Park Service. Forty percent come from Illinois. And peak season starts now.

The trouble with sand flow along the 15 miles of national park shoreline stems primarily from three man-made structures: the Michigan City Harbor, completed in the early 1900s; Port of Indiana, built in the late 1960s; and Gary-U.S. Steel Harbor, also constructed early in the last century. Another factor is what the National Park Service calls "engineered peninsulas" created primarily for industrial expansion and amounting to more than 4,000 acres of land extending into the lake.

The effect is a disruption of the littoral drift, which is the flow of sediment generally from east to west along the shoreline. On one side of the structures, sand builds up. On the other, waves gouge the beaches.

Before industrial and residential development, that shoreline included swamps, marshes, dunes, oak savannas and prairies — all of which allowed the sand flow to achieve equilibrium.

That started changing perhaps as early as 1834, when construction of the Michigan City Harbor began, and continues today.

It's unclear precisely how much sand and sediment waves drive out of eroding areas. But the National Park Service calculates that the beach at Mount Baldy, on the far eastern end of the park, loses about 4.5 feet per year. The 126-foot-high dune has been closed since July 2013, when a 6-year-old boy was swallowed by a hole and buried under 11 feet of sediment for three hours. He survived.

The highest accumulation, or accretion, was found at the Port of Indiana, in the western section of the park, where sediment accumulates at a rate of about 7.6 feet per year, the National Park Service calculates.

"Every mile you go along the lakefront," Barker said, "you experience something different in terms of shoreline issues."

`The Kennedy Compromise'

The person many point to as being responsible for complications swirling around Indiana Dunes National Lakeshore is a president who generally basks in a flattering glow of history: John F. Kennedy.

By the time he was elected president in 1960, Indiana's southern shore of Lake Michigan had for decades been recognized as a rare natural environment, in part through the efforts of University of Chicago botanist Henry Cowles. The scientist, who died in 1939, brought international attention to an intricate ecosystem that today ranks third-highest in plant diversity among all national parks and is known as the place where the several ecological plant zones converge.

Residents first proposed a national park in 1915, but others in the region pushed for industrial uses on the lakefront, including an international port. In 1963, Kennedy offered "The Kennedy Compromise," which allowed both. Three years later, Sen. Paul Douglas of Illinois ushered through legislation that created the 8,300-acre Indiana Dunes National Lakeshore.

Four expansions nearly doubled the park's size over the years, but industrial, commercial and residential pockets also exist in or near the national lakeshore, as does a 2,200-acre state park with 3 miles of lakeshore. The entire shoreline between the west and east ends of the national park runs 21 miles, but only 15 are in the Indiana Dunes National Lakeshore.

Beyond creating environmental complications, the compromise also has created tensions over land use, but Barker and National Park Service spokesman Bruce Rowe said the compromise was a practical solution to a challenging problem.

Geof Benson is Town Council president of Beverly Shores, which is surrounded by the national park. He said resentment became particularly intense when the Park Service began buying homes in the 1970s. He added that many of the industries that moved to the lakefront could have received the same benefits if they'd gone inland 10 miles and "connected a pipe" to the lake.

"They didn't view the lake as an attraction," Benson said. "The compromise made things interesting and difficult. ... It's hard to go back and change things, so we try and work together to move forward as best as possible."

But he and others have concerns with the Park Service proposal, known as the Shoreline Restoration and Management Plan/Draft Environmental Impact Statement and numbering almost 300 pages. Released in July 2012, it calls for "beach nourishment," or pumping about 180,000 cubic yards of sand and related sediment per year to areas of the park.

Although the Park Service has no specific shoreline restoration plan, the U.S. Army Corps of Engineers has delivered sand to eroding beaches in the park for decades. But "studies conducted since 1985 have shown that sediment placed at the eastern end of the park erodes entirely within two to five years," according to the Park Service's July 2012 report.

"It made sense to do more of a comprehensive, all-inclusive plan," said the National Park Service's Rowe, "rather than piecemeal things."

Berms and money

The more controversial component of the restoration proposal is a "submerged cobbled berm" of rock placed about 100 yards from shore on the far eastern end of the park with a length of 6,500 feet. The top of the berm would end about 4 feet below the water surface.

The Park Service says the berm "would reduce shoreline erosion by breaking wave energy in the near shore, thus allowing for greater sediment retention."

Benson and Barker's organization, as well as The Nature Conservancy and a regional conservation land trust, favor a different approach. It's called "sand bypass" — the hydraulic or mechanical movement of sediment from areas of accumulation to those that are eroding.

In a five-page response to the proposal, Save the Dunes, The Nature Conservancy and the Shirley Heinze Land Trust note that the berm "is a new engineering solution that has not been tested on the Great Lakes." It might accelerate erosion west of it, deteriorate in effectiveness in a relatively short time, endanger fish and lead to water quality problems and "aesthetic/odor issues," the groups said.

"I have my doubts" that the berm would be effective, Benson said. "The lake is strong enough to move away a beach, a road and houses. Why isn't it going to move a cobbled berm?"

Beyond those concerns, the plan lacks one key player: the Indiana Department of Natural Resources, which manages Indiana Dunes State Park. After initially working with the National Park Service and Corps of Engineers, the IDNR opted out of the plan.

IDNR spokesman Phil Bloom said his agency detected that the Park Service and the Corps disagreed on parts of the plan and "we did not want to get between two federal agencies that we often work with cooperatively." The IDNR also declined to sign an agreement that it perceived would pass jurisdictional authority of the state park's shoreline to the federal agencies, Bloom said.

At the moment, Rowe said, the National Park Service is assessing public comments and compiling a final plan that he said should be ready by late November. But even if all the agencies, residents and other relevant parties agree on the proposal, the shoreline restoration plan remains unfunded.